With many advantages as high security, large storage, and better portability, IC card is being used widely in many fields such as bank system, entrance guard system, bus charging system, computer, telecommunication, security etc. since the first IC card was born in the world, which makes people's life to become more convenient. The connection between IC card and people's social life becomes closer and closer and people keeps on requiring more from IC card in social life. Contact IC card has many disadvantages such as easily wear-out, usage limited by environment, which limit the usage of the contact IC card in many fields. The appearance of contactless (or non-contact) IC card solves the problem caused by the disadvantages of contact IC card and the requirement of the contactless IC card is increased.
Conventionally, the card readers for the two kinds of IC card are different. So two kinds of card readers were born: contact card reader and contactless (or non-contact) card reader. With the development of society and progress of technology, one kind of card reader can not satisfy requirement for read and write operation of both the two kinds of IC card. With the development of science and technology, a dual-interface card reader which can read both the contact IC card and contactless IC card appears. The dual-interface card reader provides at least one card reader socket for contact IC card and at least one antenna board for contactless IC card. Generally the hardware circuit of contact IC card reader socket is located in the RF magnetic field formed by the antenna board for contactless IC card (RF card), which makes the size of the card reader to be smaller. But when the dual-interface card reader is working, the magnetic field formed by the antenna board for contactless IC card will interfere the work of the hardware circuit of the contact IC card reader socket, which may cause the failure of identifying and operating contact IC card or decrease the successful rate of data interaction.
In order to reduce the RF interference inside the dual-interface card reader, the card reader applies two different kinds of operation modes: contact IC card reading mode and contactless IC card reading mode. The card reader chooses only one of the modes at a certain time, which avoids RF interference. But the card reader can not read a contact IC card and a contactless IC card simultaneously, which decreases the working efficiency of the dual-interface card reader. Especially in places where flow of reading card is large, the normal work and life of people will be influenced.
In addition, reducing of the RF interference can be implemented by extending the distance between the contact IC card socket and contactless IC card antenna board, which will make the size of the dual-interface card reader bigger. That brings much inconvenience for fixing a dual-interface card reader.